The invention concerns battery hand lamps comprising a supply unit and a lamp unit.
Prior art battery and hand lamps have the disadvantage of a relatively low luminous efficiency because in an incandescent lamp only a small percentage of the supplied electric energy is transformed into light. Substantially better is the luminous efficiency on fluorescent tubes. If impulses of very high luminosity are desired they can be obtained by electric flash tubes. Fluorescent tubes as well as flash tubes require relatively high operating voltages. Therefore, a converter device must be used to convert relatively low battery voltage into a relatively high voltage as is required by incandescent tubes or flash tubes.
When high operating voltages are used, it is absolutely necessary to protect the necessary electric or electronic parts against moisture. Up to the present time this has not been possible on battery hand lamps or only at very high expense, so that such lamps did not survive in the market.